How to compress a PDF for email without making it unreadable
Get a PDF under the email attachment limit: what makes files large, which compression level to choose and how to check the result.
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Most email providers limit attachments to around 20–25 MB. Scanned documents and photo-heavy PDFs blow past that easily. The good news is that large PDFs are usually large for one reason: images.
What makes a PDF big
- High-resolution photos or scans, often 300 dpi or more.
- Embedded full fonts that are barely used.
- Old revisions and unused objects saved inside the file.
Choosing a level
- Light — keeps quality, best for documents you'll print.
- Balanced — good for email and screens; the usual choice.
- Strong — smallest file, with visibly softer images.
Check before you send
Open the compressed file and zoom into the smallest text and any signatures. If they look fuzzy, go one level lighter. Keep the original as your archive copy.